Testing device



M. w. DAVIS.

TESTING DEVICE.

APPLICATION FILED APR. I4, 1919.

Patented Apr. 13, 1920.

EEK/[Davis I N VEN TOR ITED STAES OFFICE MAXWELL WM. DAVIS, OF WESTHAVEN, CONNECTICUT.

TESTING DEVICE.

Specification of Letters Patent.

Patented Apr. 13., igi fid.

Application filed April 14, 15519. Serial No. 290,058.

To all whom it may concern:

Be it known that I, MAXWELL WM. DAvis,

a citizen of the United States, residing at West Haven, in the county ofNew Haven 1 and State of Connecticut, have invented new and usefulImprovements in Testing Devices, of which the following is aspecification.

This invention comprehends the provision of a testing device, designedfor use by electricians, for testing spark plugs, fuses, motor troubleand electric light wiring. and in general all trouble work.

The invention aims to provide a simple device which can be carried aboutthe per son finding a use for the same and embodies among otherfeatures, a casing closed by an insulated contact plate, the lattercarrying an electric bulb adapted to project light rays through anopening in the casing, when the circuit is closed through batteriesdisposed within the casing.

One of the chief characteristics ofthe invention resides in the use of aresilient element of novel construction, designed for association withthe electric light bulb and used to maintain a plurality of drybatteries fixed relatively end to end within the casing and spaced fromthe walls of the latter.

Another object of importance resides in giving the contact plate asmaller diameter than the insulated member therefor whereby the latterprojects beyond the major portion of the edge of the plate to protectthe same; and shaping the plate to provide the latter with'a contactprojection which is cut away to accommodate itself to various parts tobe tested. p

The nature and advantages of the invention will be better understoodwhen the following detailed description is read in connection with theaccompanying drawings, the invention residing in the construction,combination and arrangement of parts as claimed. I

In the drawings forming part of this specification like numerals ofreference indicate similar parts of the several views and wherein Figure1 is a perspective view of the device.

Fig. 2 is a longitudinal sectional view therethrough.

Fig. 3 is a detail view of the contact plate or cover.

Fig. i is a similar view of the insulating plug.

Fig. 5 is a detail view of the resilient element for holding thebatteriesfixed relatively within the casing.

A device constructed in accordance with my invention essentiallyembodies a tubular casing 10 constructed from suitable material, and ofany desired dimension. One end of the casing is closed by a screw cap 11which carries a binding post 12 havin a portion disposed within thecasing when the cap is associated therewith. the major portion of thebinding post projecting outwardly from the bottom to accommodate aclamping screw 13 of usual construction. The screw is adapted to clampone end or" the wire or cord 14 to the binding post. A plurality of drybatteries '15 are inserted within the casing through the opposite endthereof, the batteries being arranged in end to end contact with thelowermost battery resting upon the binding post 12 and thus held spacedfrom the bottom cap 11. As shown, the batteries are slightly smaller indiameter than the similar dimension of the casing 10 and consequentlythe batteries are spaced from the walls of the latter. If desired thebatteries 15 may be wrapped in an adhesive sheet of suitable material 16which will serve to insulate the upper cell from shorting with the case10.

A plug 17 of suitable insulating material such as fiber or the like isinserted within the open or upper end of'the casing 10, the plug havingan annular flange 18 which re poses upon the upper edge of the casing10. and a' threadedbore 19 which receives the threaded stem 20 of anelectric light bulb 21. The bore 19 is open at both ends of the plug topermit the terminal of the bulb 21 to engage the metallic contactingplate or disk 23 which is secured to the plug 17 in any suitable manner.such as for instance by removable fastening elements 24. The

contacting plate or disk 23 is smaller in diwith certain parts of acircuit when testing said parts, and the projection 25 is cut away orindented as at 26 to permit the contact plate to accommodate itself tosaid parts. For instance, in testing a spark plug or the like, thebinding post thereof would be received within the cut away portion 26 ofthe disk 23 thus allowing the latter to rest upon the binding screw withwhich binding posts are generally provided. It is of course manifestthat the plug 17 can be readily separated from the casing 10 when it isdesired to replace either the electric light bulb 21 or the batteries15.

\Vith a view of maintaining the batteries 15 fixed relatively in a givenposition within the casing 10, I employ a ring 27 which receives thestem 21 of the electric light bulb whereby the latter provides a supportfor said ring. Projecting from the periphery of the ring 27 is aresilient finger 28 Which is curved throughout its length to conform tothe curvature of the bulb 21, the finger 28 terminating beneath the bulband adapted to engage the end of the adjacent battery'lo. The inner endof the plug 17 provides a bearing surface for the ring 27, and with theresilient finger 28 bearing against the adjacent battery 15, the saidbatteries are, held under tension in their given position within thecasing 10. If desired, the flexible element 14 may be provided with aspringclip at one end to be readily attached to any article to betested. It is of course to bennderstood that any part of the casing 10When closed with the contacting plate or disk 23 will illuminate thebulb 21, and the rays therefrom will be projected through an opening 29in the casing 10 in the vicinity of the bulb. The device is not verylarge and can be conveniently carried in the vest pocket or about theperson finding use for the same, and the device cannot be shortcircuited and the batteries run down because the batteries are designedto fit within the casing 10 in the manner shown, and because the caseand batteries are of the same polarity. The light rays from theminiature bulb 21 shows up very clear at a reasonably good distance,-andgives instant results when seeking the source of trouble in electricalsystems.

, While I have shown and described what I consider the preferredembodiment of the invention, I desire to have it understood that thesame is merely illustrative, and that I do not limit myself to the exactconstruction and arrangement disclosed, and that such changes may beresorted to when desired as fall within the scope of what is claimed.

\Vhat I claim is 1. A device of the class described comprising a casing,a binding post at one end of the casing, an insulated contact plate atthe opposite end thereof, a plurality of dry batteries arranged end toend within the casing, and spaced from the walls thereof, an electriclightbulb carried by said plate, an annulus surrounding said bulb and aspring finger carried by the annulus and engaging one of said batteriesto hold the latter fixed relatively within the casing.

2. A device of the class described comprising a casing, a binding postat one end of the casing, an insulated contacting disk at the oppositeend of the casing, the insulating material projecting beyond theperiphery of the disk for the major portion of its circumference, theremaining portion of the circumference of the disk projecting beyondsaid insulating material to provide a contacting projection, an electriclight bulb carried by the insulated plate, and a battery arranged withinthe casing.

In testimony whereof I aflix my signature.

MAXWELL WM. DAVIS.

